Cam-operated rotary fluid displacement device



CAM-OPERATED ROTARY FLUID DISPLACEMENT DEVICE Filed Sept. 25, 1963 Jan. 25, 1966 w. F. MULLER ETAL 4 sheets-Sheet l i 1 F 2 82 Fm?- 'f vw ,52

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CAM-OPERATED ROTARY FLUID DISPLACEMENT DEVICE Filed Sept. 25, 1963 4 Sheets-Sheet 2 1e 4. r i/ 56 b l6 b 540.

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Jan. 25, 1966 w. F. MULLER ETAL 3,230,891

CAM-OPERATED ROTARY FLUID DISPLACEMENT DEVICE Filed Sept. 25, 1963 4 Sheets-Sheet 5 Inveritors: H' euMdkta 'ma vdev- 2. m

United States Patent 3,230,891 CMVI-OPERATED ROTARY FLUID DISPLACEMENT DEVICE Wolf F. Muller, 205 E. 63rd St., New York, N.Y., and Reginald S. Lanier, Rte. 5, Wayzata, Minn. Filed Sept. 25, 1963, Ser. No. 311,516 6 Claims. (Cl. 103-143) The present invention relates to an improved rotary fluid displacement device of the intermittent vane movement type in which cam operation is achieved with minimal wear and maximum ability to retain the original construction tolerances.

In theory rotary fluid displacement devices are characterized by high available torque and horsepower in relation to size and a freedom from the vibration and noise inherent in reciprocating mechanisms. To date, however, these devices have not found the application that their theoretical advantages would indicate. In the case of rotary devices using sliding vanes, a major problem has existed in providing suitable sliding vanes and operating mechanisms therefor. In the case of such devices using continuously rolling vanes, one of the major problems is to provide adequate bearings for the respective vanes. In the case of devices using intermittently rotated vanes, a problem has existed of effectively rotating and orienting the vanes over a long and useful life. For these and other reasons, rotary fluid displacement devices, despite the many efforts to make them practical, have not gone into general use.

In the intermittently rotated vane type of device th housing defines a cylindrical cavity having a plurality of shoes defining a lesser diameter. The rot-or is located in this cavity and is of diameter suflicient to form a fluid seal in relation to the shoes. The rotor has a plurality of vane-receiving cavities, each of which has a vane that in radial position reaches to the surface of the housing cavity to form a seal and in circumferential position tucks within the confines of the rotor to pass the shoes. A very important advantage of this type of device resides in the fact' that the vanes are held in fixed position in relation to the rotor during the time they seal the working spaces. Consequently the bearings of the vanes are not required to withstand the driving forces when under rotation. And during the periods between the working strokes, when the vanes do rotate, the vanes in this type of device may be free of substantial fluid forces.

Despite the above and other advantages the intermittently rotated vane type of device has been found to have a decidedly limited life and to be characterized by substantial noise in operation. We have discovered that this is due to the cam mechanism used to rotate and to orient the vanes. This mechanism is required to perform an unusually critical and exact function. During the periods the vanes are in radial seal-defining position, the cam mechanism must orient and hold the vanes to a high degree of accuracy. This isnot only to avoid loss of seal in relation to the working chamber but in addition is necessary to preclude substantial rotation against the bearings while full operating fluid force is applied. Such rotation, even if relatively small, places a heavy burden on the bearings because of the very heavy forces resulting from working fluid pressure. During other periods of operation, when the cam mechanism is required to accelerate and decelerate the vane to change it between radial and circumferential position, the cam mechanism must impart relative high angular accelerations and decelerations to the vane. Since the time required for these rotations of the vane is relatively short in relation to the total time of one rotor rotation, the angular accelerations are many times those apparent from a mere consideration of the rotor angular velocity.

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We have discovered that it is critically important to the effective operation of an intermittently rotated vane type of device to maintain precise operation of the cam mechanism. We do not know entirely Why this is so. It is believed, however, that once an undue looseness in the cam mechanism develops at any point, progressive wear and deterioration sets in that generates eccentric forces on the rotor and otherwise ultimately leads to rotor lock up and failure. Moreover, we have discovered that the initial looseness in the cam mechanism is developed in considerable measure by skidding of the cam follower roller as it is required to rotate first in one direction and then in the opposite direction as it orients and accelerates the vane. While the wear thus created is seemingly small and unimportant, it has been found that it has a most important relationship to the progressive deterioration that ultimately leads to failure, and that the useful life of the device can be greatly increased by a construction that avoids skidding reversals of cam follower rotation.

In accordance with the present invention an improved intermittently rotated vane type of device is provided in which the cam mechanism does not require skidding reversals of the cam follower rollers. Pursuant to the invention, at least two cam followers are provided for each vane, and each is rotated intermittently in a single direction. Periods of coasting rotation occur between periods of intermittent rotation. Consequently, the cam followers may rotate at high angular velocities without undergoing correspondingly high angular accelerations, the vanes may be subjected to high angular accelerations without imposing like angular accelerations on the cam followers, and

the cam followers are not required at any time to skid to a stop and undergo skidding accelerations to opposite rotations. In addition, in the preferred form of the apparatus of the present invention, the vanes are held in radial orientation by the joint action of the cam followers which engage inner and outer cam faces in such fashion as to continue their rotations in a single direction.

It is therefore a general object of the present invention to provide an improved rotary fluid displacement device of the type having intermittently rotated vanes and in which vane rotation is achieved through the use of cam' mechanism in which the followers are intermittently driven in a single direction and coast between driving.

periods.

It is a further object of the present invention to provide an improved rotary fluid displacement device of the type having intermittently rotated vanes and in which the vanes are oriented in the radial direction through the use Further it is an object of the present invention to provide an improved rotary fluid displacement device of the type having intermittently rotated vanes in which the cam mechanism is elfective to orient and to rotate the vanes in a manner that does not involve skidding reversals of the cam follower parts and thereby, for a prolonged useful period, maintains the initial close tolerances of the unit and forecloses the institution of the progressive build-up of looseness that ultimately brings about failure.

Still another object of the present invention is to provide an improved rotary fluid displacement device characterized by minimal cam follower wear which is nevertheless simple in construction, reliable in operation, can be easily assembled, and in other respects provides a useful commercial device having a prolonged life and minimum noise, vibration, and other undesirable effects.

Patented Jan. 25, 1966 The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, together with further objects and advantages thereof will best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a side view, in section, of the hydraulic device embodying the rotatable vane and vane operating means of the present invention;

FIGURE 2 is a sectional view taken along lines 2--2 of FIGURE 1;

FIGURE 3 is a view in perspective of the vane and cam means associated therewith;

FIGURE 4 is an enlarged fragmentary view of the cam track and the cam followers of the vane operating means;

FIGURE 5 is a view of the cam track in which the cam followers are guidingly received illustrating the guiding and positioning function of the track;

FIGURES 5a through 5d are enlarged fragmentary views of the cam operating means illustrating cam operation during vane orientation from circumferential to radial position.

FIGURE 6 is a graphic representation of the vane position during operation of the rotary fluid device;

FIGURE 7 is a graphic presentation of the relative velocity of the vane of the fluid device of the present invention; and

FIGURE 8 is a graphic presentation of the acceleration of the vanes during rotation and orientation from one position to the succeeding position during operation of the fluid device set forth herein.

Referring more particularly now to FIGURE 1 of the drawings the hydraulic device is indicated generally at 10. The device 10 includes a housing defined by end sections 12 and 14 and a central section 16. The central section 16 is provided with recesses 18 therein extending about either face of said central section adjacent the outer peripheral portion of said section. The end sections 12 and 14 are provided with flanges 20 and 22 extending from the inner edges thereof. The flanges 20 and 22 are adapted to be received within the recesses 18 of the central section 16. Recesses 24 and 26 are provided in the end faces of the end sections 12 and 14, respectively, radially outboard the flanges 20 and 22, respectively. O-rings '28 and 30 are adapted to be received within the recesses 24 and 26, respectively. The O-rings serve to define a fluid tight seal at the interface between the end sections 12 and 14 and the central section 16 of the hydraulic device.

End section 12 is provided with an opening 32 in the outer wall thereof, said opening defining a recess 34 intermediate the faces of said wall. An O-ring is adapted to be received within the recess 34 of the opening 32.

A bearing 38 is supported by the end section 12 of the housing in coaxial relation with the opening 32 of said end section. A hearing 40 is supported by the end section 14 of the housing in coaxial relation with the opening 32 of the section 12.

A shaft 42 is rotatably supported within the housing of the hydraulic. device by the bearings 38 and 40 mounted therein. The shaft 42 extends through the opening 32 of the section 12 into the fluid chamber defined within the central section of the housing and then into supported engagement with the bearing 40.

The shaft 42 is provided with a recess 44 extending along a portion of the length thereof. End plates 46 and 48 and the rotor 50 are adapted to be slidably received overthe shaft 42 and to be keyed thereto by the key 52. The key 52 is received partially in the recess 44 of the shaft 42 and partially within a mating recess defined in each of the end plates 46 and 48 and the rotor 50. In this manner the end plates and the rotor are non-rotatably secured to the shaft 42 of the hydraulic device.

4 End plates 46 and 48 define end closure members extending along either side of the rotor and the central section 16 of the fluid device. Thus, the fluid chamber of the device is defined by the end plates 46 and 48, the rotor 50 and the central section 16 of the apparatus.

As illustrated in FIGURE 2 of the drawings, the fluid chamber of the apparatus may be defined in two sections 54 and 56. The chamber 56 defines inlet and outlet ports 56a and 56b. Chamber 54 defines inlet and outlet ports 54a and 54b.

Shoes 16a and 16b extend between the two fluid chambers 54 and 56, noted herein-above, and define a fluid seal between said chambers as set forth in detail hereinbelow. Thus, fluid flow through the fluid chamber 54 may be defined [from the port 54a through the chamber 54 defined by the housing and to the post 5412 to (be discharged from the device. Likewise counter flow may be defined in the opposing chamber 56 from the port 56a through the chamber 56 and then to the port 5612 of the apparatus to be discharged from the device. With the above noted arrangement it can readily be seen that the apparatus may be employed as a double action fluid pum as a fluid tmotor, or as a fluid driven pump wherein one chamber is employed to drive the rotor-vane assembly and the other chamber to pump fluid. Other modifications may readily be suggested to one using the device. The hydraulic device set forth herein in defined in greater detail in 'copending application Serial Number 212,548, filed July 26, 1962, now abandoned.

Rotor 50 of the device is mounted on the shaft 42, said rotor defining a plurality of recesses 58 extending inwardly from the outer periphery of said rotor. Rotatable vanes 64 of the fluid device are adapted to be disposed within the recesses '58 of the rotor for rota-table, fluid engaging operation therein (as defined herein'below).

As shown in greater detail in FIGURE 3, the vanes 64 each include a shaft 62. Support plates 74 and 76 are adapted to he mounted in oppositely disposed position along a section of the shaft 62 intermediate the ends thereof. A relatively resilient member 78 is adapted to be aflixed between the plates 74 and 76.

A team follower support arm 66 is non-rotatab'ly affixed to the outer terminals of each of the vane shafts 62, as illustrated in FIGURES 1 and 3. A shaft 68 is aflixed to each of the arms 66 of the vanes 64, said shaft 68 being non-rotatably secured to said anrn. A pair of cam followers 70 and 72 are rotatably mounted on the outer terminal portion of each of the shafts 68. The inboard cam follower 70 on each shaft 68, as illustrated, is slightly larger than the outboard cam follower 72 on each shaft 68.

The resilient member 78 is adapted to extend completely across the cylinder defined by each of the recesses 58 of the rotor 50. The member 78 defines a seal during the working stroke along 54 and: 56 at one end thereof along the base of the cylinders 58, and at the other end thereof along the outer walls 54c and 560 of the fluid chambers. The vane thus, in working position, defines a fluid block (between the inlet and outlet ports of the fluid chambers. The fluid either may be pushed before the vane (if the specific device is serving as a pump) or the vane may be pushed along with the fluid (if the de vice is serving as a motor and thus is being driven).

During passage through the fluid chambers 54 and 56 of the fluid device the vanes 64 are oriented to radial position as illustrated in FIGURE 2 of the drawings. The vanes alternately are oriented to circumferential position to pass beneath the shoes 16:; and 16b of the fluid device. The fluid seal defined by the varies between the base of each of the recesses 58 and the outer walls of the fluid chambers is defined only when the vanes are oriented to radial position to traverse the fluid chambers.

Each of the end plates 46 and 48 of the device 10 are provided with a series of openings extending therethrough at radially spaced intervals thereabout. The

shafts 62 of each of the vanes 64 are adapted to be mounted within the openings 60 of the end plates. As shown in FIGURE 1 of the drawings, the openings 69 of the oppositely disposed end plates 46 and 48 are so axially aligned to receive vane shafts 62 therein. The shafts 62 of the vane structures are rotatably mounted within the openings 60 of the end plates 46 and 48. The end plates are adapted to rotate in unison with the rotor 50, said plates being moved along by engagement :with the rotating vanes 64 of the device through the vane shafts. The end plates 46 and 48 are in interfacial sliding engagement with the side walls of the central section 16 of the housing. Slight spacing is required between the end plates and the central section 16 in order to permit free movement of the rotor 50 of the apparatus.

As the vanes 64 move through the fluid chambers defined hereinabove and approach the opposite port thereof they must pass under the shoes 16a or 1612, which shoes define the fluid seal between the opposite chambers of the device. In order to pass under the shoes the vanes must be oriented to circumferential position and moved into the recesses 58 within which they are mounted.

Cam plates 80 and 82 are provided at either end of the internal housing cavity of the device to provide means for rotating the vanes 64, in combination with the cam followers and associated apparatus, .to position the vanes 64 fully within the recesses 58 of the rotor 50 during traverse of the shoe areas 16a and 16b of the housing and to reorient the vanes 64 to radial position during the working stroke.

Cam plate 80 is rigidly aflixed to the end section 12 of the housing. Cam plate 82 is rigidly afiixed to end section 14 of the housing. The cam plates 80 and 82 define recesses therein, as indicated generally at 34, each of said recesses defining outer and inner cam tracks, 86 and 88, respectively. The cam track 86 of each of the cam plates is smaller in radial dimension than the cam track 88 of each plate. The outer cam wheel 72 of each of the vanes 64 is adapted to be guidingly received within the outer earn track 86 of each cam plate 80 and 82, respectively. The inner cam follower 70 of each vane 64 is adapted to be guid-ingly received within the inner cam track 88 of each cam plate of the device. The cam followers are provided at each end of each vane 64 to provide positive control during each portion of the cycle during operation of the device. The balanced control provided by this means of operation gives rise to longer effective operating life of the device.

In operation of the apparatus set forth herein it is seen that an advantage of the disclosed vane operating means resides in the avoidance of the reversal of the cam followers for each transition of the vanes 64 from radial working position to circumferential position wherein the vanes are disposed within the recesses 58 for movement past the shoes 16a and 16b of the device.

The cam followers and cam tracks comprising the vane operating means of the present rotating vane fluid device are constructed such that one cam follower engages its mating cam track for movement of the vane in one direction and the other cam follower engages the remaining cam track for rotation of the vane in the other direction; Thus the inactive cam follower continues to rotate in the same direction upon being moved away from its track. While the cam follower may lose a small amount of the angular velocity imparted to it during engagement with the cam track it will still be at a relatively high velocity prior to entry of the next active period thereof. The increase in velocity required to bring it to full operating engagement will be a relatively small amount in comparison to the velocity essential toelfect a direction reversal and acceleration to working velocity in the opposite direction. A still greater advantage, of course, resides in the fact that with the present construction inertial forces inherent in reversing the angular direction of rotation of the cam follower during subsequent transitional movements of the vane are avoided. Also skidding of the followers and the high functional wear associated therewith is avoided. One cam follower is employed for each directional movement of the vanes 64 and to this extent the follower for that directional movement is always rotating in the same direction during operation with the angular velocity of the follower varying a relatively small amount between active and inactive periods of said follower.

As will be seen from FIGURE 4 of the drawings the periphery of the inside cam follower is shown in spaced relation to the cam track 88 when the cam follower 72 is in engagement with the cam surface of the outer cam track 86. At a subsequent angular position in the operating cycle of the device the member 66 will shift the shaft 68 upwardly with respect to the drawing of FIGURE 4 to move the cam follower 70 into engagement with the cam track 88 of the cam plates and to move the follower 72 into spaced relation with its cam track. The follower 72 will continue to rotate in the same direction on the shaft 68, its angular velocity depreciating slightly due to hearing friction, possible fluid or air resistance, or the like. During the next subsequent transition the arm 66 and shaft 68 will again move the follower 72 into engagement with its cam track and move the follower '70 into spaced relation with its cam track. As indicated hereinabove the follower 7 9 will continue to rotate on its shaft 68 in the direction imparted to it during contact with the cam track 83, which direction of rotation will be opposite to that imparted to the follower 72 during operation of the device. It thus is seen that slight movements of the camming means will bring the alternate cam followers into and out of active position with its respective cam track while permitting the inactive cam follower to rotate continuously in the direction imparted to it during its active engagement with its cam track.

Operation of the camming mechanism will best be understood by reference to FIGURES 5 through 5d of the drawings. Only the cam track (eg. 8%)), the cam followers and the vane 7 8(shown in this manner for illus-- trative purposes) of the device are presented in FIGURES 5 through 5d. The axis of the shaft 62 of the vanes 64' As shown in FIGURE 5a of the drawings the vane 64 is illustrated in the top position wherein the member 78 will be in circumferential position within the recess 58 to pass beneath the shoe 16a. As the vane rotates about the device the member 78 will remain centered on the base cylinder path A as set forth hereinabove. Continued rotation of the rotor 50 will cause the vane and associated cumming members to move to the right as in FIGURE 5a, the cam followers moving along the cam track of the member 80. The cam follower 70 will be in engagement with the outer peripheral face of the track 86 in the positions illustrated in FIGURE 5a. As the cam member reaches the position at the right in FIGURE 5a the continued rotation of the rotor 50 will cause the vane to rotate in position whereby the cam follower 70 will be caused to leave its camming surface and the cam follower 72 will be brought into engagement with its camming surface 88. The cam follower 72 will be rotating in direction opposite to that of follower 70 from preceding operation of the apparatus and will continue to move in the same direction along its cam track. There will be minimal skidding of the follower since its rotation will be substantially the same as that required to move it along the cam track in accord with movement of the rotor 50, there being only slight loss in rotational energy due to frictional losses or the like. Thus the cam follower 72 will be substantially at terminal velocity for effectivev control operation and movement along its cam track 88 to control the movement of the vane through its working stroke; As shown in FIGURES 5b and 5c the vane member continues to rotate in position with respect to the body of the fluid device until it moves to radial position with respect to the rotor 50 wherein the member 78 defines the seal between the base of the recess 58 and the wall of the fluid chamber of the device to .be acted upon by or to act upon the fluid within the chamber.

In orientation of the vane 64 to circumferential position for passage by shoe 16b the cam follower roller 70 will, under action of movement of the rotor 50 continuously along its path, move to a position of engagement with its cam track 86 to position the vane within the recess 58 of the rotor 50. The member 78 will precede the cam followers at this position of movement, the cam roller 70 of the cam mechanism continuing to rotate in the samedevice with reference to rotor position. At the rotor position, that is with the reference point of the rotor in line with a vertical plane through the axis of the rotor, the vane is moving with respect to a point in space but is stationary with respect to the rotor. There thus is uniform vane movement with respect to the rotor of the fluid device while the vane passes by the shoe 16a of the device. At point F on the cycle of rotation of the rotor 50 the vane 64 undergoes a reversal of position as noted hereinabove in orientation from circumferential position to radial position in the fluid device. Upon rotation to radial position the vane position is changing at the same rate as the rotor position and thus is stationary with respect to the rotor but is moving at a constant rate with respect to a point in space or with respect to the body of the fluid device. Thus at the 90 rotor position the vane again is horizontally inclined as indicated by the intersection of the vane position line with the horizontal position line. As the rotor moves from the 90 position clockwise to position G it moves from horizontal position to approximately a 60 angle with respect to a horizontal plane through the device, said vane moving continuously in an arcing manner through the fluid chamber of the fluid device. At rotor position G, which may, for example, be adjacent chamber 54a of the fluid device, the vane undergoes reorientation to circumferential position wherein it quickly passes from the 60 position in one plane through horizontal at 180 rotor position to approximately 60 position in a plane oriented. at 90 to said oneplane at rotor position H. From rotor position H to rotor position I the vane is stationary with respect to said rotor but moving with respect to the body of the fluid device. The vane position moves from 60 in one plane at H, through horizontal vane position at 270 and then to 60 with respect to the horizontal at I adjacent port 56a, for example. The vane again is reoriented at rotor position I to circumferential position for passage by the shoe 16a of the fluid device and a new cycle begins.

FIGURE 7 graphically illustrates the velocity of the vanes during a complete cycle of the rotor, and is correlated with the graphical van position chart of FIGURE 6. As illustrated, the velocity of the vanes during orientation from circumferential to radial position will be relatively high in that the vane must rotate in angular direction through substantially 240 in a brief interval in order to define sealing relation between the base of the recess 53 and the wall of the fluid chamber, as set forth hereinabove. This velocity pattern is graphically illustrated at intervals F and H in FIGURE 7. The velocity of movement of the vanes during orientation from radial to circumferential is relatively low in that the vane is moved only through about 69 or about one-fourth the distance during orientation from circumferential to radial positions. The movement is substantially less during transiion to circumferential position and therefore the terminal velocity of the vane during such orientation is substantially less, as graphically illustrated at positions G and J of FIGURE 7. The acceleration, representing a function of the torque imposed upon the camming members of the fluid device, is represented graphically in FIGURE 8 of the drawings. As noted the acceleration is greatest during transition of the vanes from circumferential to radial positions than vice versa in that the vanes must move through a greater angular distance during the same time interval as required during transition from circumferential to radial positions.

As noted hereinabove, the fluid device of the present invention is divided into two separate chambers. The fluid seal between the chambers is defined by the shoeslfia and 16b in combination with the rotor 50 of the fluid device. As shown more clearly in FIGURE 2 of the drawings, the outer periphery of the rotor 50 defines sub stantially the same base circle as the arced faces of the shoes 16a and 16b adjacent the outer portions of said shoes. Each of the recesses 58 of the rotor 50 is smaller in circumferential dimension across their open faces than the overall circumferential dimension of the shoes 16a and 16b, respectively. As shown in FIGURE 2, the outer periphery of the rotor 50 is adapted sealingly to engage the arced faces of the shoes 16a and 16b to define the fluid seal between the chambers 54 and 56 of the fluid device. The recessed area in the central portion of eachof the shoes 16a and 16b provides pressure relief for the chambers 58 so that the vanes 64 are not under a differential pressure during the time that they are passing by either of the shoes.

Thus, it is seen, in summary, that the fluid device of the present invention provides vane control means for positive, precise vane control during all portions of the vane cycle during operation of said device. The dual cam operating means for each vane avoids the skidding reversals and inherent wear patterns of single cam vane control means. This apparently is most significant for long, effective operation of the apparatus in that the first increment of vane operator wear is avoided that would otherwise give rise to conditions permitting cumulative self destruction of the apparatus.

While a specific embodiment of the present invention is shown and. described it will, of course, be understood that other modifications and alternative constructions may be used Without departing from the true spirit and scope of the invention. It is intended by the appended claims to cover all such modifications and alternative constructions as fall within their true spirit and scope.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A rotary fluid displacement device comprising in combination a housing defining a cylindrical cavity of predetermined diameter having an axis;

a cylindrical rotor having a lesser diameter than said predetermined diameter and disposed in said cavity with its axis coaxial with the axis of said cavity, said cylindrical rotor having a plurality of vanereceiving complementary cavities disposed symmetrically about its surface, said last cavities each having an axis parallel to the axis of the rotor and disposed on a common base circle such that each said last cavity forms a portion of a cylinder which, when extended, is tangential to the cylindrical cavity of the housing;

vane elements rotatably mounted by shafts located in each of said last cavities, respectively, each vane element being movable between a circumferential position and a radial position, in the circumferential position being within the confines of the rotor, and in the radial position being in sealing relation with the wall of the cylindrical cavity of the housing and the wall of the corresponding cavity of the rotor, said shafts moving with the rotor with their axes defining a base circle;

means defining shoe elements extending between the cavity of the housing and the cylindrical rotor, whereby fluid working spaces are defined in the annular spaces between the respective shoe elements and the vanes when in radial positions, said apparatus including means to admit fluid into said spaces, respectively, and to discharge fluid therefrom;

and cam elements effective to move said vanes cyclically to circumferential orientations as they pass said shoes and to radial orientations in said working spaces, said cam elements including crank arm elements on the vanes, respectively, at least two cam follower rollers on each crank arm element, and means attached to the housing defining separate stationary cam tracks for the respective follower rollers of each vane, one of said cam tracks being shaped to receive the corresponding followers and rock the cam when the vane movement requires cam follower rotation in one direction, and the other of said cam tracks being shaped to receive the corresponding followers and rock the scam when the vane movement requires cam follower roller rotation in the opposite direction, the cam followers being displaced from track engaging and operative position to disengagement with their respective tracks by the continued rotation of the rotor and vanes along the base circle where the cam followers at predetermined circumferential positions are positively moved by the crank arms to said operative and disengaged positions, whereby the cam follower rollers are set in motion during operation of the device in opposite directions and during the operation of the device are either driven in rolling action in those directions or are coasting and the cam follower and cam wear associated with reversals of cam follower rotation are avoided, the incident wear on the cam followers and cams is avoided, and the looseness that otherwise would lead to asymmetrical rotor and vane displacements and ultimate failure of the fluid displacement device is avoided.

2. A rotary fluid displacement device comprising in combination:

a housing defining a cylindrical cavity of predetermined diameter having an axis;

I a shaft rotatably mounted within said housing and having its axis in axially aligned relation with the axis of said housing;

a cylindrical rotor mounted on said shaft, said rotor having a lesser diameter than said predetermined diameter, said rotor disposed within said cavity, said cylindrical rotor having a plurality of vane-receiving cavities disposed in radially uniformly spaced relation about the surface thereof, said vane-receiving cavities each having an axis parallel to the axis of the rotor on said shaft and disposed on a comrnon base circle such that each said vane-receiving cavity form-s a portion of a cylinder which, when extended, is tangential to the cylindrical cavity of the housing;

vane elements rotatably mounted by shafts and located in each of said vane-receiving cavities, respectively, each vane element being movable between a circumferential and a radial position, in the circumferential position being within the confines of the rotor, and in the radial position being in sealing relation with the wall of the cylindrical cavity of the housing and the wall of the corresponding cavity of the rotor, said shafts moving with the rotor with their axes moving in a common base circle;

means defining shoe elements extending between the cavity of the housing and the cylindrical rotor,

whereby fluid working spaces are defined in the annular spaces between the respective shoe elements and the vanes when is radial positions;

and cam elements afiixed by arms to said vanes and effective to provide critical cyclical vane orientation during operation of the rotary fluid device, said cam elements including at least two cam followers associated with each vane and means attached to said housing defining separate stationary cam tracks for the followers of each vane, one of said cam tracks adapted to receive one of said cam followers and to rock the vane to one position, the other of said cam tracks adapted to receive the other of said cam followers and to rock the vane to another position, the cam followers being displaced from track engaging and operative position to disengagement with their respective tracks by the continued rotation of the rotor and vanes along the base circle where the cam followers at predetermined circumferential posi-tions are positively alternately moved by the arms to said operative and disengaged positions, respectively, whereby the cam followers are set in motion during operation of the device in opposite directions and during the operation of the device are either in driven relation in those directions or are coasting and the cam follower and cam wear associated with reversals of cam follower rotation are avoided, the incident wear on the cam followers and cams is avoided, and the looseness that otherwise would lead to asymmetrical rotor and vane displacements and ultimate failure of the fluid displacement device is avoided.

3. A rotary fluid displacement device comprising in combination a cylindrical rotor having an axis and of diameter to form a fluid seal with the shoe elements of. the cavity and disposed in the cavity with its axis coaxial with the axis of the cavity, said cylindrical rotor having a plurality of vane-receiving complementary cavities disposed at uniform angular spacings about its surface, said last cavities each having an axis'par-allel to the axis of the rotor and disposed on a common base circle such that each of said vane-receiving cavities forms a portion of a cylinder which, when extended, is tangential to the cylindrical cavity of the housing;

vane elements rotatably mounted by shafts and located in each of said last cavities, respectively, each vane element having a long axis andeifective with the long axis in circumferential position in relat-ion to the rotor to nest within theconfines of the cylindrical rotor and with the long axis in radial position to extend to fluid seal relation to the surface of the cylindrical cavity at said working chambers, said shafts moving with the rotor with their axes moving in a common base circle; and,

cam elements effective to rotate the vanes to circumferential positions of their long axes to pass the shoes and to radial positions of their long axes to form fluid seals across the working spaces, said cam elements including crank means on each vane and including at least two cam follower rollers eccentr-ioally located in relation to the vane axis, and means defining a fixed cam follower groove for each of said rollers, one of the cam follower grooves being shaped to engage its cam followers for acceleration of the vane in one sense and the other cam follower groove being shaped to engage its camfollower 1 l rollersfor accelenation of the vane in opposite sense, the cam followers being displaced from the track engaging and operative position to disengagement with their respective tracks by they continued confines of the cylindrical rotor and with the long axis in, radial position to extend to fluid seal relation to the surface of the cylindrical cavity at said work- 12 form a fluid seal with theshoe elements of the cavity and disposed in the cavity with its axis coaxial with the axis of the cavity, said cylindrical rotor having a plurality of vane-receiving complerotation of the shafts along thebase circle where the 5 mentary cavities disposed at uniform angular spaccam followers at predetermined circumferential poings about its surface, said last cavities each havsitions are positively alternately moved by the crank ing an axis parallel to the axis of the rotor and means, to said operative and disengaged positions, disposed on a common base circle such that each of respectively, whereby each of the cam follower said vane-receiving cavities forms a portion of a rollers is intermittently rotated in a single direction cylinder which, when extended, is tangential to the without. reversals duringthe course of operation of cylindrical cavity of the housing; the device, vane elements located in each of said last cavities, rethe number of vanes being suflicient in relation to the spectively, each vane element having a long axis and number of shoes and the period each vane is in radial eflective with the long axis in circumferential posiposition to close each working space at all times. tion in relation to the rotor to nest within the con- 4, A rotary fluid displacement device comprising in fines of the cylindrical rotor andwith the long axis combination: in radial position to extend to fluid seal relation to a housing defining a cylindrical cavity of predetermined the surface of the cylindrical cavity at said workdiameter having an axis and having a plurality of ing chambers; and, shoe elements extending inwardly of the cavity to a 0am lem n effective t rotate the nes t0v C cumpredetermined lesser diameter, thereby defining apluferential positions of their long axes to pass the rality of circumferentially spaced working chamshoes and to radial positions of their long axes to bers separated by said shoes, and fluid inlet and outform fluid seals across the working spaces, said cam let ports to. said chambers, respectively; elements including crank means on each vane and I cylindrical rotor having an axis and of diameter to including at least two cam follower rollers eccenform a fluidseal with the shoe elements of the cavity trically located in relation to the vane axis, and and disposed in the cavity with its axis coaxial means defining a fi Cam'fOHOWeY groove for each with the axis of the cavity, said cylindrical rotor havof said rollers, one of the cam follower grooves being-a plurality of vane-receiving complementary caving shaped to engage its cam follower for accelities disposed at uniform angular spacings about its eration of the vane in one sense during periods of surface, said last cavities each having an axis paralvane acceleration by engagement of the side closest lel to the axis of the rotor and disposed on a comhe a S 0f the rotor and to engage the same side mon base circle such that each of said vane-receiving of the follower first during other periods and the avitie form a p'option of a cylinder whi h, when other of the cam follower grooves being shaped to extended, is tangential to the cylindrical cavity of engage its cam follower for acceleration of the vane e Q l in the opposite sense during periods of vane accelvane elements located in each of said last cavities, reoration by engagement on the side most remote spectively, each vane element having a long axis from the axis of the rotor and to engage the same and effective. with the long axis in circumferential side of the follower first during other erio s; position i relation to the rotor to nest within the thenumber of vanes being suflicient in relation to the number of shoes and the period each vane is in radial position to close each working space at all times.

6. A rotary fluid displacement device comprising in combination a housing defining a cylindrical cavity of predetermined ing chambers; and, can elements effective to. rotate the vanes to circum- 5 ferential positions of their long axes to pass the shoes and to radial positions of their long axes to form fluid seals across the working spaces, said cam elements, including crank means on each vane and diameter having an axis and having a plurality of shoe elements extending inwardly of the cavity to a predetermined lesser diameter, thereby defining a including at least bwq 0am follower rollers eccenplurality Of circumferentially spaced working chamtrically, located in relationtov the vane axis,and means hers Separated y Said 811068, nd fl inlet and defining a fixed cam follower groove for each of let ports to said chambers, respectively; said rollers, the cam follower groovesbeing shaped cylindrical rotor having all aXiS d v0f diameter to to c'qnstra in the vanes to padial pqsifions to form form a flllld seal with the S1106 elements 0f the cavity seals in said-working spaces, one of. the cam grooves and disposed ill the cavity With ltS axis coaxial With b i fi ti first, m engage it cam on th id the axis of the cavity, said cylindrical rotor having a closest to the axis of the rotor and the other of plurality of vane-receiving complementary cavities the cam grooves being effective first to engage its disposed at uniform angular spacings about s cam 11 idg most remote from th axis of th face, said last cavities each having an axis parallel rotor, whereby the cam followers, orient the vane 0 to axis of the rotor and POS On a ommon Without reversals of cam follower. direction, base circle such that each of said vane-receiving h number f vanes b i fli i t i l ti t th carities forms a portion of a cylinder which, when number of shoes and. the period each, vane is in extended, is tangential to the cylindrical cavity of radial position to. close each working space at all thehousillg; times! vane elements located in each of said last cavities, re- 5. A rotary fluid displacement device comprising in spectively, eaCh Vane element having a long axis and i i effective with the long axis in circumferential position in relation to the rotor to nest Within. the confines of the cylindricalrotor and with the long axis in radial position to extend to fluid seal relation to the surface of the cylindrical cavity at said working chamber; and,

cam elementseffective to rotate the; vanes to circumferential positions along their long axes to passthe shoes and to radial positions of their long'axes to a housing defining a cylindrical cavityofpredetermined diameter. having an axis and having a plurality of shoe elements extending inwardly of'the cavity to a 7n predetermined lesser diameter, thereby defining a plurality of circumferentially spaced working; chambersv separatedfby said shoes, and. fluid inlet and outlet ports to said chambers,.respectively;

a cylindrical rotor having an axis and of diameter to 13 form fluid seals across the working spaces, said cam elements including crank means on each vane and including a pair of cam follower rollers eccentrically located in relation to the vane axis, and means defining a fixed cam follower groove for each of said rollers, said cam follower groove defining two cam follower guiding surfaces one of said surfaces being of greater lateral dimension than the other, the other of said surfaces being in juxtaposed spaced relation with the said one of said surfaces, one of said pair of cam follower rollers adapted to be guidingly received on each surface of the cam elements, the diameter of said rollers being less than the lateral dimension of its respective guiding surface, one of the cam follower surfaces being shaped to engage its roller for acceleration of the vane in one sense during periods of vane acceleration by engagement on the side closest the axis of the rotor and to engage the same side of the roller first during other periods, and the other of the cam follower surfaces being shaped to engage its roller for acceleration of the vane in the opposite sense during periods of vane acceleration by engagement on the side most remote from the axis of the rotor and to engage the same side of the follower first during other periods, the number of vanes being sufficient in relation to the number of shoes and the period each vane is in radial position to close each working space at all times.

References Cited by the Examiner UNITED STATES PATENTS 1,595,496 8/1926 Beggs 91150 2,247,429 7/1941 Aikman 103-140 X 2,489,800 11/1949 Muller 103-143 2,632,400 3/1953 Marsh 103143 2,896,545 7/1959 Brulle 103143 FOREIGN PATENTS 5,429 1826 Great Britain. 464,096 4/ 1937 Great Britain.

DONLEY I. STOCKING, Primary Examiner.

JOSEPH H. BRANSON, JR., Examiner. 

1. A ROTARY FLUID DISPLACEMENT DEVICE COMPRISING IN COMBINATION: A HOUSING DEFINING A CYLINDRICAL CAVITY OF PREDETERMINED DIAMETER HAVING AN AXIS; A CYLINDRICAL ROTOR HAVING A LESSER DIAMETER THAN SAID PREDETERMINED DIAMETER AND DISPOSED IN SAID CAVITY WITH ITS AXIS COAXIAL WITH THE AXIS OF SAID CAVITY, SAID CYLINDRICAL ROTOR HAVING A PLURALITY OF VANERECEIVING COMPLEMENTARY CAVITIES DISPOSED SYMMETRICALLY ABOUT ITS SURFACE, SAID LAST CAVITIES EACH HAVING AN AXIS PARALLEL TO THE AXIS OF THE ROTOR AND DISPOSED ON A COMMON BASE CIRCLE SUCH THAT EACH SAID LAST CAVITY FORMS A PORTION OF A CYLINDER WHICH, WHEN EXTENDED, IS TANGENTIAL TO THE CYLINDRICAL CAVITY OF THE HOUSING; VANE ELEMENTS ROTATABLY MOUNTED BY SHAFTS LOCATED IN EACH OF SAID LAST CAVITIES, RESPECTIVELY, EACH VANE ELEMENT BEING MOVABLE BETWEEN A CIRCUMFERENTIAL POSITION AND A RADIAL POSITION, IN THE CIRCUMFERENTIAL POSITION BEING WITHIN THE CONFINES OF THE ROTOR, AND IN THE RADIAL POSITION BEING IN SEALING RELATION WITH THE WALL OF THE CYLINDRICAL CAVITY OF THE HOUSING AND THE WALL OF THE CORRESPONDING CAVITY OF THE ROTOR, SAID SHAFTS MOVING WITH THE ROTOR WITH THEIR AXES DEFINING A BASE CIRCLE; MEANS DEFINING SHOE ELEMENTS EXTENDING BETWEEN THE CAVITY OF THE HOUSING AND THE CYLINDRICAL ROTOR, WHEREBY FLUID WORKING SPACES ARE DEFINED IN THE ANNULAR SPACES BETWEEN THE RESPECTIVE SHOE ELEMENTS AND THE VANES WHEN IN RADIAL POSITIONS, SAID APPARATUS INCLUDING MEANS TO ADMIT FLUID INTO SAID SPACES, RESPECTIVELY, AND TO DISCHARGE FLUID THEREFROM; AND CAM ELEMENTS EFFECTIVE TO MOVE SAID VANES CYCLICALLY TO CIRCUMFERENTIAL ORIENTATIONS AS THEY PASS SAID SHOES AND TO RADIAL ORIENTATIONS IN SAID WORKING SPACES, SAID CAM ELEMENTS INCLUDING CRANK ARM ELEMENTS ON THE VANES, RESPECTIVELY, AT LEAST TWO CAM FOLLOWER ROLLERS ON EACH CRANK ARM ELEMENT, AND MEANS ATTACHED TO THE HOUSING DEFINING SEPARATE STATIONARY CAM TRACKS FOR THE RESPECTIVE FOLLOWER ROLLERS OF EACH VANE, ONE OF SAID CAM TRACKS BEING SHAPED TO RECEIVE THE CORRESPONDING FOLLOWERS AND ROCK THE CAM WHEN THE VANE MOVEMENT REQUIRES CAM FOLLOWER ROTATION IN ONE DIRECTION, AND THE OTHER OF SAID CAM TRACKS BEING SHAPED TO RECEIVE THE CORRESPONDING FOLLOWERS AND ROCK THE CAM WHEN THE VANE MOVEMENT REQUIRES CAM FOLLOWER ROLLER ROTATION IN THE OPPOSITE DIRECTION, THE CAM FOLLOWERS BEING DISPLACED FROM TRACK ENGAGING AND OPERATIVE POSITION TO DISENGAGEMENT WITH THEIR RESPECTIVE TRACKS BY THE CONTINUED ROTATION OF THE ROTOR AND VANES ALONG THE BASE CIRCLE WHERE THE CAM FOLLOWERS AT PREDETERMINED CIRCUMFERENTIAL POSITIONS ARE POSITIVELY MOVED BY THE CRANK ARMS TO SAID OPERATIVE AND DISENGAGED POSITIONS, WHEREBY THE CAM FOLLOWER ROLLERS ARE SET IN MOTION DURING OPERATION OF THE DEVICE IN OPPOSITE DIRECTIONS AND DURING THE OPERATION OF THE DEVICE ARE EITHER DRIVEN IN ROLLING ACTION IN THOSE DIRECTIONS OR ARE COASTING AND THE CAM FOLLOWER AND CAM WEAR ASSOCIATED WITH REVERSALS OF CAM FOLLOWER ROTATION ARE AVOIDED, THE INCIDENT WEAR ON THE CAM FOLLOWERS AND CAMS IS AVOIDED, AND THE LOOSENESS THAT OTHERWISE WOULD LEAD T ASYMMETRICAL ROTOR AND VANE DISPLACEMENTS AND ULTIMATE FAILURE OF THE FLUID DISPLACEMENT DEVICE IS AVOIDED. 